The present invention relates to a patterning method for use in production of a color filter, etc. for a liquid crystal display.
In a known method of forming a pattern on a color filter for a liquid crystal display, a pattern is formed by photolithography on a light shielding film of Cr or the like formed on a glass substrate so as to produce a black matrix and then, colored patterns of red, green and blue are formed on the substrate by dying, pigment dispersion, printing, etc.
In dying, after photosensitive water-soluble resist such as gelatin has been coated on the glass substrate, a predetermined pattern is obtained by exposure and development. In addition, by dying and fixing, colored patterns are obtained. By repeating this process three times, colored layers of red, green and blue are formed.
In pigment dispersion, colored photoresist in which pigment is dispersed is coated on the glass substrate and then, a predetermined pattern is obtained by exposure and development. By repeating this process three times, colored patterns of red, green and blue are formed.
Such methods as litho offset printing and intaglio offset printing are used for printing. In litho offset printing, ink on a pattern portion of a print is transferred onto an elastic rubber member and then, is printed on the substrate. On the other hand, in intaglio offset printing, ink is filled on the pattern portion and unnecessary ink is scraped from the pattern portion by a scraper. Subsequently, ink is transferred onto an elastic rubber member and then, is printed on the substrate. In any one of the printing methods, colored inks of red, green and blue are sequentially printed on the same glass substrate so as to form colored patterns, respectively.
In such conventional dying and pigment dispersion employing photolithography, the processes are complicated and production apparatuses are also expensive, thereby resulting in an increase in the production cost of the color filter. Meanwhile, in known printing, since the pattern has an arcuate sectional shape in which film thickness at it central portion is different from that of its opposite end portions, the pattern is not flat and thus, nonuniformity in film thickness is likely to take place.